/* Copyright (c) 2006-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "str.h"
#include "imap-match.h"
#include "mail-storage.h"
#include "mailbox-list-subscriptions.h"
#include "mailbox-list-iter-private.h"
#include "mailbox-list-index.h"

static bool iter_use_index(struct mailbox_list *list,
			   enum mailbox_list_iter_flags flags)
{
	struct mailbox_list_index *ilist = INDEX_LIST_CONTEXT_REQUIRE(list);

	if ((flags & MAILBOX_LIST_ITER_SELECT_SUBSCRIBED) != 0) {
		/* for now we don't use indexes when listing subscriptions,
		   because it needs to list also the nonexistent subscribed
		   mailboxes, which don't exist in the index. */
		return FALSE;
	}
	if ((flags & MAILBOX_LIST_ITER_RAW_LIST) != 0 &&
	    ilist->has_backing_store) {
		/* no indexing wanted with raw lists */
		return FALSE;
	}
	if (mailbox_list_index_refresh(list) < 0 &&
	    ilist->has_backing_store) {
		/* refresh failed */
		return FALSE;
	}
	return TRUE;
}

struct mailbox_list_iterate_context *
mailbox_list_index_iter_init(struct mailbox_list *list,
			     const char *const *patterns,
			     enum mailbox_list_iter_flags flags)
{
	struct mailbox_list_index *ilist = INDEX_LIST_CONTEXT_REQUIRE(list);
	struct mailbox_list_index_iterate_context *ctx;
	pool_t pool;
	char ns_sep = mail_namespace_get_sep(list->ns);

	if (!iter_use_index(list, flags)) {
		/* no indexing */
		return ilist->module_ctx.super.iter_init(list, patterns, flags);
	}

	pool = pool_alloconly_create("mailbox list index iter", 2048);
	ctx = p_new(pool, struct mailbox_list_index_iterate_context, 1);
	ctx->ctx.pool = pool;
	ctx->ctx.list = list;
	ctx->ctx.flags = flags;
	ctx->ctx.glob = imap_match_init_multiple(pool, patterns, TRUE, ns_sep);
	array_create(&ctx->ctx.module_contexts, pool, sizeof(void *), 5);
	ctx->info_pool = pool_alloconly_create("mailbox list index iter info", 128);
	ctx->ctx.index_iteration = TRUE;

	/* listing mailboxes from index */
	ctx->info.ns = list->ns;
	ctx->path = str_new(pool, 128);
	ctx->next_node = ilist->mailbox_tree;
	ctx->mailbox_pool = ilist->mailbox_pool;
	pool_ref(ctx->mailbox_pool);
	return &ctx->ctx;
}

static void
mailbox_list_get_escaped_mailbox_name(struct mailbox_list *list,
				      const char *raw_name,
				      string_t *escaped_name)
{
	const char escape_chars[] = {
		list->mail_set->mailbox_list_storage_escape_char[0],
		mailbox_list_get_hierarchy_sep(list),
		'\0'
	};
	mailbox_list_name_escape(raw_name, escape_chars, escaped_name);
}

static void
mailbox_list_index_update_info(struct mailbox_list_index_iterate_context *ctx)
{
	struct mailbox_list_index_node *node = ctx->next_node;
	struct mailbox *box;

	p_clear(ctx->info_pool);

	str_truncate(ctx->path, ctx->parent_len);
	/* the root directory may have an empty name. in that case we'll still
	   want to insert the separator, so check for non-NULL parent rather
	   than non-empty path. */
	if (node->parent != NULL) {
		str_append_c(ctx->path,
			     mailbox_list_get_hierarchy_sep(ctx->ctx.list));
	}
	mailbox_list_get_escaped_mailbox_name(ctx->ctx.list, node->raw_name,
					      ctx->path);

	ctx->info.vname = mailbox_list_get_vname(ctx->ctx.list, str_c(ctx->path));
	ctx->info.flags = node->children != NULL ?
		MAILBOX_CHILDREN : MAILBOX_NOCHILDREN;
	if (strcmp(ctx->info.vname, "INBOX") != 0) {
		/* non-INBOX */
		ctx->info.vname = p_strdup(ctx->info_pool, ctx->info.vname);
	} else if (!ctx->prefix_inbox_list) {
		/* listing INBOX itself */
		ctx->info.vname = "INBOX";
		if (mail_namespace_is_inbox_noinferiors(ctx->info.ns)) {
			ctx->info.flags &= ENUM_NEGATE(MAILBOX_CHILDREN |
						       MAILBOX_NOCHILDREN);
			ctx->info.flags |= MAILBOX_NOINFERIORS;
		}
	} else {
		/* listing INBOX/INBOX */
		ctx->info.vname = p_strconcat(ctx->info_pool,
			ctx->ctx.list->ns->prefix, "INBOX", NULL);
		ctx->info.flags |= MAILBOX_NONEXISTENT;
	}
	if ((node->flags & MAILBOX_LIST_INDEX_FLAG_NONEXISTENT) != 0)
		ctx->info.flags |= MAILBOX_NONEXISTENT;
	else if ((node->flags & MAILBOX_LIST_INDEX_FLAG_NOSELECT) != 0)
		ctx->info.flags |= MAILBOX_NOSELECT;
	if ((node->flags & MAILBOX_LIST_INDEX_FLAG_NOINFERIORS) != 0)
		ctx->info.flags |= MAILBOX_NOINFERIORS;

	if ((ctx->ctx.flags & (MAILBOX_LIST_ITER_SELECT_SUBSCRIBED |
			       MAILBOX_LIST_ITER_RETURN_SUBSCRIBED)) != 0) {
		mailbox_list_set_subscription_flags(ctx->ctx.list,
						    ctx->info.vname,
						    &ctx->info.flags);
	}

	if ((ctx->ctx.flags & MAILBOX_LIST_ITER_RETURN_NO_FLAGS) == 0) {
		box = mailbox_alloc(ctx->ctx.list, ctx->info.vname, 0);
		mailbox_list_index_status_set_info_flags(box, node->uid,
							 &ctx->info.flags);
		mailbox_free(&box);
	}
}

static void
mailbox_list_index_update_next(struct mailbox_list_index_iterate_context *ctx,
			       bool follow_children)
{
	struct mailbox_list_index_node *node = ctx->next_node;

	if (!ctx->prefix_inbox_list && ctx->ctx.list->ns->prefix_len > 0 &&
	    strcmp(node->raw_name, "INBOX") == 0 && node->parent == NULL &&
	    node->children != NULL) {
		/* prefix/INBOX has children */
		ctx->prefix_inbox_list = TRUE;
		return;
	}

	if (node->children != NULL && follow_children) {
		ctx->parent_len = str_len(ctx->path);
		ctx->next_node = node->children;
	} else {
		while (node->next == NULL) {
			node = node->parent;
			if (node != NULL) T_BEGIN {
				/* The storage name kept in the iteration context
				   is escaped. To calculate the right truncation
				   margin, the length of the name must be
				   calculated from the escaped storage name and
				   not from node->raw_name. */
				string_t *escaped_name = t_str_new(64);
				mailbox_list_get_escaped_mailbox_name(ctx->ctx.list,
								      node->raw_name,
								      escaped_name);
				ctx->parent_len -= str_len(escaped_name);
				if (node->parent != NULL)
					ctx->parent_len--;
			} T_END;
			if (node == NULL) {
				/* last one */
				ctx->next_node = NULL;
				return;
			}
		}
		ctx->next_node = node->next;
	}
}

static bool
iter_subscriptions_ok(struct mailbox_list_index_iterate_context *ctx)
{
	if ((ctx->ctx.flags & MAILBOX_LIST_ITER_SELECT_SUBSCRIBED) == 0)
		return TRUE;

	if ((ctx->info.flags & MAILBOX_SUBSCRIBED) != 0)
		return TRUE;

	if ((ctx->ctx.flags & MAILBOX_LIST_ITER_SELECT_RECURSIVEMATCH) != 0 &&
	    (ctx->info.flags & MAILBOX_CHILD_SUBSCRIBED) != 0)
		return TRUE;
	return FALSE;
}

const struct mailbox_info *
mailbox_list_index_iter_next(struct mailbox_list_iterate_context *_ctx)
{
	struct mailbox_list_index *ilist = INDEX_LIST_CONTEXT_REQUIRE(_ctx->list);
	if (!_ctx->index_iteration) {
		/* index isn't being used */
		return ilist->module_ctx.super.iter_next(_ctx);
	}

	struct mailbox_list_index_iterate_context *ctx =
		(struct mailbox_list_index_iterate_context *)_ctx;
	bool follow_children;
	enum imap_match_result match;

	/* listing mailboxes from index */
	while (ctx->next_node != NULL) {
		T_BEGIN {
			mailbox_list_index_update_info(ctx);
		} T_END;
		match = imap_match(_ctx->glob, ctx->info.vname);

		follow_children = (match & (IMAP_MATCH_YES |
					    IMAP_MATCH_CHILDREN)) != 0;
		if (match == IMAP_MATCH_YES && iter_subscriptions_ok(ctx)) {
			/* If this is a) \NoSelect leaf,
			   b) not mailbox_list_layout=index
			   and c) NO-NOSELECT is set, try to rmdir the leaf
			   directories from filesystem. (With
			   mailbox_list_layout=index the
			   \NoSelect mailboxes aren't on the filesystem.) */
			if (ilist->has_backing_store &&
			    mailbox_list_iter_try_delete_noselect(_ctx, &ctx->info,
								  str_c(ctx->path))) {
				/* Deleted \NoSelect leaf. Refresh the index
				   later on so it gets removed from the index
				   as well. */
				mailbox_list_index_refresh_later(_ctx->list);
			} else {
				mailbox_list_index_update_next(ctx, TRUE);
				return &ctx->info;
			}
		} else if ((_ctx->flags & MAILBOX_LIST_ITER_SELECT_SUBSCRIBED) != 0 &&
			   (ctx->info.flags & MAILBOX_CHILD_SUBSCRIBED) == 0) {
			/* listing only subscriptions, but there are no
			   subscribed children. */
			follow_children = FALSE;
		}
		mailbox_list_index_update_next(ctx, follow_children);
	}
	return mailbox_list_iter_default_next(_ctx);
}

int mailbox_list_index_iter_deinit(struct mailbox_list_iterate_context *_ctx)
{
	struct mailbox_list_index *ilist = INDEX_LIST_CONTEXT_REQUIRE(_ctx->list);
	if (!_ctx->index_iteration)
		return ilist->module_ctx.super.iter_deinit(_ctx);

	struct mailbox_list_index_iterate_context *ctx =
		(struct mailbox_list_index_iterate_context *)_ctx;
	int ret = ctx->failed ? -1 : 0;

	pool_unref(&ctx->mailbox_pool);
	pool_unref(&ctx->info_pool);
	pool_unref(&_ctx->pool);
	return ret;
}
